The nearby areas of sea shore all over the world are facing acute shortage of land and also suffer from the erosion of sea shores. Further, the availability of fresh water and fine sand for construction activity is getting scarce in coastal areas and are to be transported from far away areas. Sea sand and sea water cannot be used for making conventional concrete due to the presence of alkaline and chloride contents. The conventional inorganic cementations cement free materials namely geo-polymeric material has emerged as an appropriate material for making cement free concrete using sea water and sea sand due their unique salt and chloride resistant properties, as otherwise these are the challenging factors in utilization of sea water and sea sand for making conventional concrete. Sea water due to high chloride content creates honey combing of structures and leads to corrosion of reinforcement in conventional cement concrete.
Geo-polymer concrete uses fly ash, a by-product created from the burning of coal. Currently, the majority of fly ash is dumped into landfills, causing environmental problems. The production of geo-polymer concrete allows fly ash to be utilized in bulk quantity. Geo-polymer concrete is also more resistant to structural damage than conventional concrete. It is also more resistant to salts, acids, seawater corrosion and fire. Therefore there is a need to develop cementations material readily and safely by utilizing sea water and sea sand. This will not only revolutionize the construction industry near the sea shores but will also make available costly land and overcome the erosion problem also.
Worldwide coastal line has vast availability of sea sand and sea water which is unutilized presently and is not suitable for any construction activity. The coastal sand being rich in high chloride and sulphate content is unfit for use as a fine aggregate in conventional cement concrete applications. The exploitation and use of river sand as fine aggregate in cement concrete has started creating an ecological and environmental imbalance and the issue of over exploitation of river sand for construction activities all over the word. It has therefore become imperative to look for an economically and technically viable option wherein the fine aggregate can be suitably replaced with coastal sand available in large quantity in world and its limitations are best used to the full advantage in making advanced geo-polymeric concrete material for various structural and non-structural applications. There is a strong potential of exploring and utilizing sea water and sea sand in the world for structural and non-structural applications.
Reference may be made to Article “Possibility of sea water as mixing water in concrete, by Nobuaki Otsukietal. August 2011 wherein the concrete utilizing sea water has been reported by using blast furnace slag and externally added corrosion inhibitor and ammonium citrate is used as anti-rusting agent. The drawbacks of the process are a) utilizes blast furnace slag is available in limited quantity as compare to fly ash b) requirement of externally added corrosion inhibitor and ammonium citrate as anti-rusting agent.
Reference may be made to article Research on using sea sand to produce cement concrete for road pavement construction by Tran Tuanhiep, science journal of transportation, Especial Issue No. 02 International cooperation Journals MADI—SWJTU, pp 8-14,2010 wherein cement concrete using sea sand and conventional cement has been reported. The drawbacks of the process are a) strength is less than traditional cement concrete. b) requirement of externally added corrosion inhibitor and ammonium citrate as anti-rusting agent.
Reference may be made to patent by Permeability and chloride penetration of concrete subjected to Gaza sea water exposure by Zaher Kuhail et al. Journal of Islamic University of Gaza vol.19, pp. 67-84-39, February 2001, wherein concrete using Gaza sea water has been reported. The drawback of this process is associated with the conventional cement concrete system.
Reference may be made to article “Study on the properties of sea sand concrete” by in Mechanic Automation and control Engineering (MACE), 2011 wherein sea sand concrete has been developed using fly ash and conventional concrete system. The drawback of this process is associated with the conventional cement concrete system.
Reference may be made to article “Durability of sea-sand containing concrete: Effects of chloride ion penetration by Yin Huiguang et al. in Mining Science and technology by vol.21, issue 1, pp. 123-127, January wherein sea sand containing concrete has been reported using conventional cement concrete system. The drawback of this process is associated with the conventional cement concrete system.
Reference may be made to Properties and application of concrete made with sea water and unwashed sea sand by Keisaburo Katano et al. In 3rd International conference on sustainable construction materials & technology http://www.claisse.info/Proceedings.htm wherein concrete has been developed using blast furnace slag, silicafume, fly ash and special admixture containing calcium nitrate. The drawbacks of the process are externally used silica fumes and calcium nitrate.
Reference may be made to article Making concrete from sand and sea water—Talk Vietnam in www.talkvietnam.com/2012/. . ./making-concrete-from-sand-and-sea-water wherein concrete from sea sand and sea water has been developed. The drawback of the process is the need of external additives.
Reference may be made to patent Sea water-mixed concrete, concrete structure constructed with the same and design method of concrete structure constructed with sea water mixed concrete by Shigeru Aoki et. al. USPTO Publication no. 2014/02 02 358 A1, March 2014 wherein concrete has been developed using sea sand sea water using slag containing cement and nitrite based admixtures and pozzolan. The drawback are externally used nitrite based admixtures and pozzolan.
Reference may be made to Thesis “Investigation of abundant treated sea sand in cement brick with the ration of 1:6 with different percentages” by Khairul Danial Bin Abd. Latif, university Malaysia Pahang, December 2010 wherein treated sea sand has been used for making cement brick. The drawback of the process is cumbersome and requires treatment of sand before using.
Reference may be made to article “Study on the properties of sea sand concrete” by Guoliang Zhang in Mechanic Automation and control Engineering (MACE) 2011 wherein concrete has been developed using sea sand concrete with fly ash. The drawback of this process is associated with the conventional cement concrete system.
Reference may be made to Article “Influence of the curing method on compressive strength and porosity of concrete mixed with sea water, marine sand and fly ash” by M. W. Tjarongeetal. in Proceedings of the 7th International Conference on Asian and Pacific Coasts (APAC), Indonesia, 2013 wherein concrete mixed has been reported using sea water, marine sand and fly ash. The drawback of this process is associated with the conventional cement concrete system.
Reference may be made to article “Thach Anh Transfers sea water-proof concrete technology to navy, PANO, 15 Mar. 2012 Wherein concrete from gravel, sea sand, seawater, cement and additives. The drawback of this process is associated with the conventional cement concrete system.
From the hitherto reported prior art and based on the drawbacks of the known processes, the various issues that need to be addressed and problems to be solved are summarized here as under. The last decades have witnessed significant achievements in the area of construction materials utilizing sea sand and sea water. However, the development of these construction materials suffers from the following drawbacks like the sea sand cannot be used for making conventional concrete without washing for removing salt content, the sea water cannot be used for making conventional concrete, the washing of sea sand uses fresh water which is a precious commodity in the vicinity of coastal areas. The use of unwashed sea sand in conventional concrete deteriorates its properties and leads to the corrosion of reinforcement of the concrete materials therefore there is a need to use epoxy coating, additives and anti-rusting agent externally on their reinforcement on utilization of sea sand and sea water in making conventional concrete.